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TEXT memmove(SB), $0
JMP move
TEXT memcpy(SB), $0
move:
MOVW R1, s1+0(FP)
MOVW n+8(FP), R3 /* R3 is count */
MOVW R1, R4 /* R4 is to-pointer */
SGT R0, R3, R5
BEQ R5, ok
MOVW (R0), R0 /* abort if negative count */
ok:
MOVW s2+4(FP), R5 /* R5 is from-pointer */
ADDU R3,R5, R7 /* R7 is end from-pointer */
ADDU R3,R4, R6 /* R6 is end to-pointer */
/*
* easiest test is copy backwards if
* destination string has higher mem address
*/
SGT $4,R3, R2
SGTU R4,R5, R1
BNE R1, back
/*
* if not at least 4 chars,
* dont even mess around.
* 3 chars to guarantee any
* rounding up to a word
* boundary and 4 characters
* to get at least maybe one
* full word store.
*/
BNE R2, fout
/*
* test if both pointers
* are similarly word aligned
*/
XOR R4,R5, R1
AND $3, R1
BNE R1, fout
/*
* byte at a time to word align
*/
f1:
AND $3,R4, R1
BEQ R1, f2
MOVB 0(R5), R8
ADDU $1, R5
MOVB R8, 0(R4)
ADDU $1, R4
JMP f1
/*
* turn R3 into to-end pointer-15
* copy 16 at a time while theres room.
* R6 is smaller than R7 --
* there are problems if R7 is 0.
*/
f2:
ADDU $-15,R6, R3
f3:
SGTU R3,R4, R1
BEQ R1, f4
MOVW 0(R5), R8
MOVW 4(R5), R9
MOVW R8, 0(R4)
MOVW 8(R5), R8
MOVW R9, 4(R4)
MOVW 12(R5), R9
ADDU $16, R5
MOVW R8, 8(R4)
MOVW R9, 12(R4)
ADDU $16, R4
JMP f3
/*
* turn R3 into to-end pointer-3
* copy 4 at a time while theres room
*/
f4:
ADDU $-3,R6, R3
f5:
SGTU R3,R4, R1
BEQ R1, fout
MOVW 0(R5), R8
ADDU $4, R5
MOVW R8, 0(R4)
ADDU $4, R4
JMP f5
/*
* last loop, copy byte at a time
*/
fout:
BEQ R7,R5, ret
MOVB 0(R5), R8
ADDU $1, R5
MOVB R8, 0(R4)
ADDU $1, R4
JMP fout
/*
* whole thing repeated for backwards
*/
back:
BNE R2, bout
XOR R6,R7, R1
AND $3, R1
BNE R1, bout
b1:
AND $3,R7, R1
BEQ R1, b2
MOVB -1(R7), R8
ADDU $-1, R7
MOVB R8, -1(R6)
ADDU $-1, R6
JMP b1
b2:
ADDU $15,R5, R3
b3:
SGTU R7,R3, R1
BEQ R1, b4
MOVW -4(R7), R8
MOVW -8(R7), R9
MOVW R8, -4(R6)
MOVW -12(R7), R8
MOVW R9, -8(R6)
MOVW -16(R7), R9
ADDU $-16, R7
MOVW R8, -12(R6)
MOVW R9, -16(R6)
ADDU $-16, R6
JMP b3
b4:
ADDU $3,R5, R3
b5:
SGTU R7,R3, R1
BEQ R1, bout
MOVW -4(R7), R8
ADDU $-4, R7
MOVW R8, -4(R6)
ADDU $-4, R6
JMP b5
bout:
BEQ R7,R5, ret
MOVB -1(R7), R8
ADDU $-1, R7
MOVB R8, -1(R6)
ADDU $-1, R6
JMP bout
ret:
MOVW s1+0(FP), R1
RET
END
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